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Chemosphere Jun 2024Disinfection by-products (DBPs) are prevalent contaminants in drinking water and are primarily linked to issues regarding water quality. These contaminants have been...
Disinfection by-products (DBPs) are prevalent contaminants in drinking water and are primarily linked to issues regarding water quality. These contaminants have been associated with various adverse health effects. Among different treatment processes, nanofiltration (NF) has demonstrated superior performance in effectively reducing the levels of DBPs compared to conventional processes and ozone-biological activated carbon (O-BAC) processes. In this experiment, we systematically investigated the performance of three advanced membrane filtration treatment schemes, namely "sand filter + nanofiltration" (SF + NF), "sand filter + ozone-biological activated carbon + nanofiltration" (SF + O-BAC + NF), and "ultrafiltration + nanofiltration" (UF + NF), in terms of their ability to control disinfection by-product (DBP) formation in treated water, analyzed the source and fate of DBP precursors during chlorination, and elucidated the role of precursor molecular weight distribution during membrane filtration in relation to DBP formation potential (DBPFP). The results indicated that each treatment process reduced DBPFP, as measured by trihalomethane formation potential (THMFP) and haloacetic acid formation potential (HAAFP), with the SF + O-BAC + NF process being the most effective (14.27 μg/L and 14.88 μg/L), followed by the SF + NF process (21.04 μg/L and 16.29 μg/L) and the UF + NF process (26.26 μg/L and 21.75 μg/L). Tyrosine, tryptophan, and soluble microbial products were identified as the major DBP precursors during chlorination, with their fluorescence intensity decreasing gradually as water treatment progressed. Additionally, while large molecular weight organics (60-100,000 KDa) played a minor role in DBPFP, small molecular weight organics (0.2-5 KDa) were highlighted as key contributors to DBPFP, and medium molecular weight organics (5-60 KDa) could adhere to the membrane surface and reduce DBPFP. Based on these findings, the combined NF process can be reasonably selected for controlling DBP formation, with potential long-term benefits for human health.
Topics: Disinfection; Drinking Water; Water Purification; Trihalomethanes; Halogenation; Water Pollutants, Chemical; Filtration; Ozone; Disinfectants; Acetates; Charcoal; Water Quality
PubMed: 38677607
DOI: 10.1016/j.chemosphere.2024.142121 -
Micromachines Mar 2024Since ozone is highly corrosive, it can substantially affect the mechanical and chemical properties of the materials; consequently, it could affect the applicability of...
Since ozone is highly corrosive, it can substantially affect the mechanical and chemical properties of the materials; consequently, it could affect the applicability of those materials in medical applications. The effect of ozone sterilization on the chemical and mechanical properties of additively manufactured specimens of biocompatible poly(methyl-methacrylate) was observed. FDM 3D-printed specimens of biocompatible PMMA in groups of five were exposed to high concentrations of ozone generated by corona discharge for different durations and at different ozone concentrations inside an enclosed chamber with embedded and calibrated ozone, temperature, and humidity sensors. A novel approach using laser-induced fluorescence (LIF) and spark-discharge optical emission spectrometry (SD-OES) was used to determine an eventual change in the chemical composition of specimens. Mechanical properties were determined by testing the tensile strength and Young's modulus. A calibrated digital microscope was used to observe the eventual degradation of material on the surface of the specimens. SD-OES and LIF analysis results do not show any detectable sterilization-caused chemical degradation, and no substantial difference in mechanical properties was detected. There was no detectable surface degradation observed under the digital microscope. The results obtained suggest that ozone sterilization appears to be a suitable technique for sterilizing PMMA medical devices.
PubMed: 38675283
DOI: 10.3390/mi15040472 -
Veterinary Sciences Apr 2024Infectious skin diseases are quite common in veterinary medicine. These diseases can be caused by both bacteria and pathogenic fungi. Antimicrobial drugs are usually...
Infectious skin diseases are quite common in veterinary medicine. These diseases can be caused by both bacteria and pathogenic fungi. Antimicrobial drugs are usually used for treatment. An alternative to these drugs could be ozonated oils with antibacterial and antifungal properties. Four different ozonated oils (linseed, hemp seed, sunflower, and olive) were tested in order to develop an optimal pharmaceutical form for the treatment of skin infections in animals. Chemical parameters such as acid and acidity value, iodine and peroxide value, viscosity, and infrared spectres were analysed. The ozonation of oils resulted in changes in their chemical composition. The antimicrobial activity of the tested oils was evaluated by determining the minimum inhibitory concentrations and zones of inhibition in agar. After ozonation, the acid content increased in all the tested oils. The highest acidity was found in linseed oil (13.00 ± 0.11 mg KOH/g; 6.1%). Hemp oil, whose acidity was also significant (second only to linseed oil), was the least acidified by ozonation (11.45 ± 0.09 mg KOH/g; 5.75%). After ozonation, the iodine value in oils was significantly reduced (45-93%), and the highest amounts of iodine value remained in linseed (47.50 ± 11.94 g Iodine/100 g oil) and hemp (44.77 ± 1.41 Iodine/100 g oil) oils. The highest number of peroxides after the ozonation of oils was found in sunflower oil (382 ± 9.8 meqO/kg). It was found that ozonated hemp and linseed oils do not solidify and remain in liquid form when the temperature drops. The results showed a tendency for the reference strains of , , and to have broader zones of inhibition ( < 0.001) than clinical strains. Overall, ozonated linseed oil had the highest antibacterial activity, and ozonated olive oil had the lowest, as determined by both methods. It was found that ozonated linseed oil was the most effective on bacteria, while the most sensitive were ATCC 25923, MRSA, and (MIC 13.5 mg/mL, 4.6 mg/mL, and 13.5 mg/mL, respectively, and sterile zones 20.67 ± 0.98 mm, 20.25 ± 0.45 mm, and 18.25 ± 0.45 mm, respectively). The aim and new aspect of this work is the characterisation of selected ozonated vegetable oils, especially hemp oil, according to chemical and antibacterial parameters, in order to select suitable candidates for preclinical and clinical animal studies in the treatment of bacterial or fungal skin infections in terms of safety and efficacy.
PubMed: 38668428
DOI: 10.3390/vetsci11040161 -
The Science of the Total Environment Jun 2024The drugs and personal care products in water sources are potential threats to the ecological environment and drinking water quality. In recent years, the presence of... (Review)
Review
The drugs and personal care products in water sources are potential threats to the ecological environment and drinking water quality. In recent years, the presence of PPCPs has been detected in multiple drinking water sources in China. PPCPs are usually stable and resistant to degradation in aquatic environments. During chlorination, chloramination, and ozonation disinfection processes, PPCPs can act as precursor substances to generate N-nitrosodimethylamine (NDMA) which is the most widely detected nitrosamine byproduct in drinking water. This review provides a comprehensive overview of the impact of PPCPs in China's water environment on the generation of NDMA during disinfection processes to better understand the correlation between PPCPs and NDMA generation. Chloramine is the most likely to form NDMA with different disinfection methods, so chloramine disinfection may be the main pathway for NDMA generation. Activated carbon adsorption and UV photolysis are widely used in the removal of NDMA and its precursor PPCPs, and biological treatment is found to be a low-cost and high removal rate method for controlling the generation of NDMA. However, there are still certain regional limitations in the investigation and research on PPCPs, and other nitrosamine by-products such as NMEA, NDEA and NDBA should also be studied to investigate the formation mechanism and removal methods.
Topics: China; Disinfection; Water Purification; Water Pollutants, Chemical; Dimethylnitrosamine; Drinking Water; Disinfectants
PubMed: 38657805
DOI: 10.1016/j.scitotenv.2024.172498 -
Water Research Jun 2024The application of ozone (O) disinfection has been hindered by its low solubility in water and the formation of disinfection by-products (DBPs). In this study,...
The application of ozone (O) disinfection has been hindered by its low solubility in water and the formation of disinfection by-products (DBPs). In this study, capacitive disinfection is applied as a pre-treatment for O oxidation, in which manganese dioxide with a rambutan-like hollow spherical structure is used as the electrode to increase the charge density on the electrode surface. When a voltage is applied, the negative-charged microbes are attracted to the electrodes and killed by electrical interactions. The contact between microbes and capacitive electrodes leads to changes in cell permeability and burst of reactive oxygen species, thereby promoting the diffusion of O into the cells. After O penetrates the cell membrane, it can directly attack the cytoplasmic constituents, accelerating fatal and irreversible damage to pathogens. As a result, the performance of the capacitance-O process is proved better than the direct sum of the two individual process efficiencies. The design of capacitance-O system is beneficial to reduce the ozone dosage and DBPs with a broader inactivation spectrum, which is conducive to the application of ozone in primary water disinfection.
Topics: Ozone; Oxides; Disinfection; Manganese Compounds; Cell Membrane; Water Purification; Electrodes; Bacteria
PubMed: 38657310
DOI: 10.1016/j.watres.2024.121608 -
Journal of Infection in Developing... Mar 2024Candida albicans and Aspergillus fumigatus are two important agents of Healthcare-associated infections. This study aimed to evaluate the antifungal activity of ozone...
INTRODUCTION
Candida albicans and Aspergillus fumigatus are two important agents of Healthcare-associated infections. This study aimed to evaluate the antifungal activity of ozone (O3) gas produced by two commercial devices against cultures of these two species.
METHODOLOGY
Sterile plastic plates were inoculated with C. albicans and A. fumigatus and placed on a countertop at three distances (30 cm, 1 m, and 2 m) and three positions in relation to the wall (near, middle, and away), considering the source of O3. Plates were exposed to O3 for one hour and incubated. After incubation, the counting of colony-forming units was performed. As a control, an inoculated plate was incubated, without being exposed to O3. Tests were carried out with two different devices (namely, Mod.I and Mod.II), with the air conditioner on and off, in triplicate.
RESULTS
Both devices showed antifungal activity. Mod. I presented better results, due to a higher flow rate. The best activity was on plates at 30 cm, middle position. Contrarily, on plates at 2m, near the wall, the inhibition activity was lower. The best results were obtained with the air conditioner off. Candida albicans was more sensitive to O3 than A. fumigatus.
CONCLUSIONS
This method of decontamination by O3 gas shows potential due to its fast and easy execution. The establishment of new protocols for hygiene and hospital disinfection using this approach should be considered, which may reduce environmental contamination by fungi and, consequently, the burden of fungal infections.
Topics: Candida albicans; Aspergillus fumigatus; Antifungal Agents; Mycoses; Microbial Sensitivity Tests
PubMed: 38635625
DOI: 10.3855/jidc.15344 -
Water Research Jun 2024In drinking water applications, an ozone exposure (Ct) based framework has been historically used to validate ozone disinfection. However, significant viral inactivation...
In drinking water applications, an ozone exposure (Ct) based framework has been historically used to validate ozone disinfection. However, significant viral inactivation can be achieved with little to no measurable ozone exposure. Additionally, ozone exposure depends on multiple water quality variables as well as the calculation/ozone measurement method used. In this study, we evaluated alternative ozone monitoring frameworks as well as the impact of water quality variables on ozone decay kinetics and virus/coliform inactivation. Here we show that both change in UV absorbance and applied O:TOC were well correlated with viral inactivation and these frameworks were resilient to changes in water quality. Both increasing temperature (12-30 ⁰C) and pH (5.5-8.4) was shown to significantly increase the ozone decay rate and decreased the resulting ozone exposure by as much as ∼90% in the case of pH. However, due to the increased reaction rate of ozone with viruses at elevated temperature and pH, there was only a minor impact (∼20% in the case of pH) in overall disinfection performance for a given O:TOC. These frameworks were also considered for variable source water with TOC (5-11 mg/L) and TSS (1.2-5.8 mg/L). Change in UV absorbance or applied ozone dose (mg/L) were the strongest indicators of disinfection performance for source waters of variable TOC, however site-specific testing may be needed to apply this framework. Challenge testing with influent nitrite indicated that ozone disinfection performance is significantly impacted (>50% reduction in inactivation) in the presence of nitrite thus enforcing the importance of accounting for this value in the applied ozone dose. Multi-point ozone dissolution was investigated as an alternative ozone application method that may present a benefit with respect to overall disinfection performance especially if nitrite was present. Developing and validating these alternative monitoring frameworks and ozone application methods is imperative in water reuse applications where unnecessary elevated ozone exposure may lead to harmful byproduct formation.
Topics: Ozone; Virus Inactivation; Water Purification; Disinfection; Drinking Water
PubMed: 38631238
DOI: 10.1016/j.watres.2024.121536 -
Nature Communications Apr 2024Animals employ different strategies to establish mating boundaries between closely related species, with sex pheromones often playing a crucial role in identifying...
Animals employ different strategies to establish mating boundaries between closely related species, with sex pheromones often playing a crucial role in identifying conspecific mates. Many of these pheromones have carbon-carbon double bonds, making them vulnerable to oxidation by certain atmospheric oxidant pollutants, including ozone. Here, we investigate whether increased ozone compromises species boundaries in drosophilid flies. We show that short-term exposure to increased levels of ozone degrades pheromones of Drosophila melanogaster, D. simulans, D. mauritiana, as well as D. sechellia, and induces hybridization between some of these species. As many of the resulting hybrids are sterile, this could result in local population declines. However, hybridization between D. simulans and D. mauritiana as well as D. simulans and D. sechellia results in fertile hybrids, of which some female hybrids are even more attractive to the males of the parental species. Our experimental findings indicate that ozone pollution could potentially induce breakdown of species boundaries in insects.
Topics: Animals; Male; Female; Drosophila melanogaster; Drosophila; Reproduction; Drosophila simulans; Carbon; Pheromones
PubMed: 38605003
DOI: 10.1038/s41467-024-47117-7 -
Journal of Pharmacy & Bioallied Sciences Feb 2024The objectives of the current study was to evaluate the disinfection efficacy of ozone, ultraviolet (UV) radiation, herbal and glutaraldehyde method for sterilization of...
OBJECTIVES
The objectives of the current study was to evaluate the disinfection efficacy of ozone, ultraviolet (UV) radiation, herbal and glutaraldehyde method for sterilization of elastomeric impression materials.
MATERIALS AND METHODS
Disinfection of elastomeric impression material was performed with each of the disinfection methods: ozone, UV radiation, herbal, and glutaraldehyde. Later microbiological analysis was performed and the colony-forming units were evaluated and compared.
RESULTS
The highest disinfection efficacy was found with glutaraldehyde, followed by ozone and UV radiation, and the least with neem herbal rinse. Intergroup comparison was highly significant.
CONCLUSION
Dry gaseous ozone and UV radiation can be used effectively for the disinfection of impressions.
PubMed: 38595356
DOI: 10.4103/jpbs.jpbs_962_23 -
Environmental Science & Technology Apr 2024Extracellular polymeric substances (EPS) ubiquitously encapsulate microbes and play crucial roles in various environmental processes. However, understanding their...
Extracellular polymeric substances (EPS) ubiquitously encapsulate microbes and play crucial roles in various environmental processes. However, understanding their complex interactions with dynamic bacterial behaviors, especially during the disinfection process, remains very limited. In this work, we investigated the impact of EPS on bacterial disinfection kinetics by developing a permanent EPS removal strategy. We genetically disrupted the synthesis of exopolysaccharides, the structural components of EPS, in , a well-known EPS-producing opportunistic pathogen found in diverse environments, creating an EPS-deficient strain. This method ensured a lasting absence of EPS while maintaining bacterial integrity and viability, allowing for real-time in situ investigations of the roles of EPS in disinfection. Our findings indicate that removing EPS from bacteria substantially lowered their susceptibility threshold to disinfectants such as ozone, chloramine B, and free chlorine. This removal also substantially accelerated disinfection kinetics, shortened the resistance time, and increased disinfection efficiency, thereby enhancing the overall bactericidal effect. The absence of EPS was found to enhance bacterial motility and increase bacterial cell vulnerability to disinfectants, resulting in greater membrane damage and intensified reactive oxygen species (ROS) production upon exposure to disinfectants. These insights highlight the central role of EPS in bacterial defenses and offer promising implications for developing more effective disinfection strategies.
Topics: Disinfection; Extracellular Polymeric Substance Matrix; Disinfectants; Chlorine; Kinetics
PubMed: 38571383
DOI: 10.1021/acs.est.4c01612